It is necessary to change automotive engine oil and oil filters periodically to prevent engine wear. The oil filters typically used in automotive engines are of a barrel cylinder type which screw on to and off of the engine block. Removing the oil filter from the engine block may be difficult and time consuming depending upon the engine design, the clearance available around the filter and the degree in which the screw on oil filter has been tightened against the engine block.
Efforts have been made to provide tools to facilitate Oil filter removal. One such device is that described in U.S. Pat. No. 4,860,617 to Robbins. Robbins describes a strap type oil filter wrench which is comprised of a long flexible strap with an adjustable loop at one end. A stop mounted to the strap prevents movement of the loop along the strap to facilitate holding the loop in an open position.
Another device is that described in U.S. Pat. No. 5,115,700 to Kaler, 2nd. Kaler, 2nd discloses a strap wrench made of a semi-rigid, form retaining planer strip wrap around. The wrap around forms a shape retaining adjustable loop held open by guides. A pull cord is attached to one end of the planer strip and wrapped around the loop to rotate the oil filter as the cord is pulled.
Another device for removing oil filters has been described and illustrated in U.S. Pat. No. 4,221,140 to Bracey, et al. The Bracey patent discloses a device having a bolt with a slot through its rod into which is fitted an endless fabric strap. The bolt has a head which is sized to fit a conventional wrench. The strap is fitted around the oil filter and as the bolt head is turned by the wrench, the strap is tightened around the filter for rotating the filter as the head is turned.
Another strap wrench is that disclosed in U.S. Pat. No. 3,962,936 to Lewis. Lewis describes a rotatable wrenching member such as a bolt having slots into which is insert both ends of a flexible strap to form a bight. The size of the bight is adjustable by sliding the bolt along the strap. Rotating the wrenching member tightens the strap and turns an annular body such as an oil filter.
Another flexible strap wrench device used to rotate tubular members is disclosed in U.S. Pat. No. 4,010,662 to Perrault. The Perrault patent discloses an apparatus that discloses a flexible strap with handles at either end. Raised ribs form a surface on one side of the strap for gripping the object to be rotated as the strap ends are pulled.
Another strap apparatus for removing oil is illustrated in Great Britain patent 1 201 663 to Arthur. The patent discloses an oil filter wrench which is comprised of shaft having two prongs, a flexible strap having loops which engage the prongs, the shaft is turned by a wrench or other means which in turn tightens the strap around the filter and turns the filter.
Still another strap wrench device is that shown in U.S. Pat. No. 4,079,642 to Scott. The Scott Patent discloses a wrench having a tension strap having a handle at one end and a buckle at the other end, a sliding or wrenching strap having one end secured to the buckle and the other end passed through the buckle to form a bight and terminated in a handle. The bight is placed around the oil filter and tighten by pull the handles which in turn rotates the oil filter.
These devices are comprised of essentially two types. One type, such as that described by Kaler, 2nd, and Robbins, utilize buckles or guides to form a bight in a strap pulled from one end. This may cause slippage of the bight around the filter during use. The second type, such as that described by Bracey, et al, Lewis and Arthur require external wrenching means such as conventional wrenches to tighten the straps. Using external wrenches may be difficult due to the limited and cramped space typically associated with engine compartments oil filters mounted to engine blocks.
Other strap wrench devices such as those described by Scott and Perrault would require the user to pull on the ends of two straps simultaneously to turn the oil filter. This may be difficult in the cramped quarters of engine compartments.
Consequently, a need exists for improvements in oil filter strap wrench designs to improve their use in cramped, limited space situations such as that associated with oil filters on engine blocks and to reduce the incidence of strap slippage when it is tightened around the filter.